Remove LegacyTagMap; OptimizedTagMap is the sole TagMap implementation (#11678)

Remove LegacyTagMap, its factory abstraction, and the trivial test enums

With one implementor, the optimized/legacy split is dead weight. Delete
LegacyTagMap and LegacyTagMapFactory; collapse the whole TagMapFactory
abstraction (TagMap.create()/create(int)/EMPTY now construct
OptimizedTagMap directly via a lazy EmptyHolder that avoids a
TagMap<->OptimizedTagMap static-init cycle). OptimizedTagMap is the sole
TagMap implementor, satisfying CHA's unique-implementor precondition.

Delete the now-trivial TagMapType/TagMapTypePair test enums and
de-parameterize their tests to plain @test; TagMapScenario (size-based)
stays. Drop stale "legacy and optimized" references from javadoc.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Remove the dead optimized.map.enabled config flag

The flag only chose between the optimized and legacy TagMap impls; with
Legacy gone it controls nothing. Remove the Config field/getter, the
GeneralConfig constant, and the metadata/supported-configurations.json
entry. Per the Config team, removing the registry entry is detected
automatically at the next release (FPD + public docs get a
"Max Version: v1.xx.0" marker), so the hard delete is the correct process.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Merge branch 'master' into dougqh/kill-legacy-tagmap

Update internal-api/src/main/java/datadog/trace/api/TagMap.java

Co-authored-by: Sarah Chen <sarah.chen@datadoghq.com>

Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

Author: dougqh

dd-trace-api/src/main/java/datadog/trace/api/config/GeneralConfig.java

@@ -118,7 +118,6 @@ public final class GeneralConfig {
   public static final String APM_TRACING_ENABLED = "apm.tracing.enabled";
   public static final String JDK_SOCKET_ENABLED = "jdk.socket.enabled";
 
-  public static final String OPTIMIZED_MAP_ENABLED = "optimized.map.enabled";
   public static final String TAG_NAME_UTF8_CACHE_SIZE = "tag.name.utf8.cache.size";
   public static final String TAG_VALUE_UTF8_CACHE_SIZE = "tag.value.utf8.cache.size";
   public static final String SPAN_BUILDER_REUSE_ENABLED = "span.builder.reuse.enabled";

internal-api/src/main/java/datadog/trace/api/Config.java

@@ -1393,7 +1393,6 @@ public static String getHostName() {
 
   private final boolean jdkSocketEnabled;
 
-  private final boolean optimizedMapEnabled;
   private final boolean spanBuilderReuseEnabled;
   private final int tagNameUtf8CacheSize;
   private final int tagValueUtf8CacheSize;
@@ -3247,7 +3246,6 @@ PROFILING_DATADOG_PROFILER_ENABLED, isDatadogProfilerSafeInCurrentEnvironment())
 
     this.jdkSocketEnabled = configProvider.getBoolean(JDK_SOCKET_ENABLED, true);
 
-    this.optimizedMapEnabled = configProvider.getBoolean(GeneralConfig.OPTIMIZED_MAP_ENABLED, true);
     this.spanBuilderReuseEnabled =
         configProvider.getBoolean(GeneralConfig.SPAN_BUILDER_REUSE_ENABLED, true);
     this.tagNameUtf8CacheSize =
@@ -5072,10 +5070,6 @@ public boolean isJdkSocketEnabled() {
     return jdkSocketEnabled;
   }
 
-  public boolean isOptimizedMapEnabled() {
-    return optimizedMapEnabled;
-  }
-
   public boolean isSpanBuilderReuseEnabled() {
     return spanBuilderReuseEnabled;
   }